This invention relates to the cleaning of spinnerette jets of a solvent-spun fibre production plant.
In the manufacture of solvent-spun fibres, such as for example Teneel cellulose fibres (Teneel is a trade mark of Courtaulds Fibres Limited), a dope comprising wood pulp dissolved in an aqueous solution of amine oxide, is pumped through a series of filters to a plurality of spinning heads. Each spinning head comprises a plurality of very thin metal plates in which thousands of spinnerette jet holes are punched. The jet holes are typically of the order of 80.mu. and are of trumpet shape.
It is vitally important to prevent the jets becoming blocked and to this extent a tremendous reliance is placed on designing filters upstream of the jets to filter the dope. Nevertheless there comes a time when it is necessary to dismantle the spinning head and clean the spinnerette jets.
In the past, the Spinnerette jets have been cleaned by soaking the spinnerette plates in hot demineralised water to regenerate the cellulose. Most of the dope can be removed this way, however, a number of jet holes remain blocked. The remaining blocked holes are usually cleaned by a combination of the use of steam cleaning, high power ultrasonic washing with water and the use of trichlorethylene ultrasonic treatment, and extremely careful inspection. The trichlorethylene ultrasonic treatment is an important stage in the present processes, but it is a relatively toxic part of the process and there is the need to reduce dependency on the use of trichlorethylene for this part of the process.
There is, therefore, a need for a reliable method of cleaning which is less dependent on the skills of inspectors searching thousands of jet holes for blockages to detect blocked holes, and which will not damage the spinnerette plates.
An object of the present invention is to provide a safe and reliable method of cleaning spinnerette jets of a spinning head of a solvent-spun fibre manufacturing plant.